When installed, run full scans with both these utilities and delete/quarantine anything found.

If the problem still persists, try the following:

If you are using Internet Explorer, close any Internet Explorer windows that may be open, then try the following.

Open windows Control Panel, open Internet Options, click the Privacy tab, place a tick in the box next to 'Turn on Pop-up Blocker', then click Apply to save the change - sites that you want to allow pop-ups for can be added to the list of Allowed Sites by clicking the Settings button, adding the web address and then clicking the Add button.

Another option you may want to consider is to download and install Firefox. When done, install the Add-on Adblock Plus